Slow-Cooker Cheeseburger Soup

Spray 5- to 6-quart slow cooker with cooking spray. In 12-inch nonstick skillet, cook beef over medium-high heat, stirring frequently, until brown; drain. In slow cooker, mix beef, onions, tomatoes and steak sauce. Cover and cook on Low heat setting 8 hours, or on High heat setting 4 hours. Stir in cheese; cover and set slow cooker to Warm heat setting. Stir occasionally while fries cook. Make waffle fries as directed on package. Serve soup topped with lettuce and waffle fries. To freeze: Store soup in quart-size resealable freezer plastic bags. Label, and freeze lying flat. To reheat: Defrost overnight in refrigerator, or in microwavable bowl on Defrost setting in microwave, stirring often. Then microwave uncovered on High 4 to 6 minutes or to 165 °F. Serve with freshly cooked waffle fries and shredded lettuce.